Marvin,
The cutter is part of the cutoff from my fire tube. 12.250 drill tube
Hey Peter
Hoping this isn’t off topic/mudding up your thread (I can delete it/get it moved if so)
Have you decided on what type of cylinder heads you will be using for your SBC engine? I was hoping to pick your brain a bit on what you felt would be better for our (woodgas) applications. From what I’ve been reading you cannot beat the vortec 350 heads if you don’t go aftermarket. Whats your thought between vortec 350, 062 castings and vortec 305, 059 castings.
from what I’ve read/ seen with my own eyes (i have both sets of heads in the garage waiting to be installed when I figure out which would be better 
).
both 305 and 350 have the same exhaust valve size 1.50
however 350 has slightly larger intake valves 350 = 1.94 vs 305 = 1.84
350 has bigger combustion chamber than 305 ( 350 = 62cc vs 305 = 58cc) so 305 heads would boost the compression up compared to the 350
not sure what the compression would be on 305 heads but guys who have done it state cannot drive with pump gas but ok with 93 octane.
350 has the “kidney” “fast burn” combustion chamber design whereas 305 has D shape standard combustion design.
I got the flow #'s here for the two heads Stan Weiss' - Cylinder Head Flow Data at 28 Inches of Water -- DFW / FLW Flow Files for use with Engine Simulation Software
but It all looks like jargon to me and can’t interpret/compare the two to heads.
To me the 305 heads (with DIY porting) would seem to be a good choice if one was willing to sacrifice the use of pump gas for some more compression (would this help woodgas?) however I don’t really want to throw a set of 305 heads on the engine if 350 heads will give the same results but allow pump gas to be used. As it stands I only really use gas to start the truck and for slight boost. I would use 93 octane with 305 heads if I only needed it for starting the engine.
Another area I’d like to hear your thoughts on relative to this is cam selection. When I got the vortec 305 heads I also grabbed the cam, roller lifters, timing gear from the same engine etc. Would you change the cam at all to take more advantage of the higher compression?
Whats your thoughts?
Thanks Dustin
Hi Dustin,
All good questions. Right now I am pondering my own wood gas engine combination. As you know, I am going the supercharged route. Very little of what I do will apply to a naturally aspirated engine. Keep in mind that I have not yet even seen a woodgas engine run,so anything I speak of is purely speculation.
With the parts that you own, I would most likely utilize the 58cc heads with a set of flat top pistons. This would be around 12+ to 1. With stock dish pistons & 58cc heads, approx 10 to 1.
Remember that there are different aftermarket piston heights, so these #s can be varied a bit.
As for head type, my choice will be Brodix, Indy or Dart. A cheaper upgrade would be
Edelbrock heads, & pistons of your choice. Maybe a Performer intake & cam. I would be careful not to lower the engine vacuum with a radical cam or intake manifold.
Warning!! — pick one change at a time ---- yes very painful, but it is the only way to accurately move forward on development.
As for your cams & timing sets, I don’t know if there will be any significant gain as actual specs are not known. Cam timing has been modified for emissions. If you purchase an aftermarket cam & timing set, you are able to degree the cam to the specs on the cam card.
Hope this helps a little ---- maybe join us on Friday night — easier to talk than type.
Peter
I think this is excellant advice PeterC.
Yes use the the less ripping turbulent combustion chamber with flat topped pistons. Woodgases do not need the kidney sheer edge. Breaks down the CO to in cylinder CO2 and soot before CO actual combustion.
Dustin the folks done woodgas camming and have talked about it say you absolutly must keep your intake vacumn up with the least valve overlapping possible. They recommend RV/Marine cam grinds dialed in as Peter says.
Regards
Steve Unruh
Found a 3.250 in. drive by wire throttle body in a junk pile. Machined all the housings off ----- seems like it should work well.
I have 4.00 in. pvc from the hay filter to the rear of the transmission, then reduced to 3.500 in. stainless tubing all the way to the engine compartment.
The tube that passes the steering shaft had to be made easily removable in order to access # 7 spark plug.
I am going to set up for a stock carb/wg combination to get my feet wet DOW. Need to get a better feel for the engine needs before supercharging.
One piece at a time will end in sweet success. Good find on the TB.
I can’t confirm this but I have heard that the 305 heads are thinner castings and can crack with the higher compression ratio. I would put them on a scale just to check for this.
Dave
Peter,
Looking great. Your under carb intake plenum looks like what I have planned for the Wood Hawg. I have a potential issue I haven’t worked out yet. This under carb feed for woodgas requires two throttle setups. I am using a 700 R4 trans which uses a cable link to the throttle valve in the trans. I have it hooked up to the carb linkage , but haven’t figured out how to also operate it from the woodgas throttle. I have read that the 700 R4 longevity is very dependent on proper throttle valve operation. In past projects, I have simply preset the trans throttle valve at about 75% and had no problems. I have been warned against this on the 700 R4, as it uses an aluminum pump not a steel pump.
Any thoughts on this?
Chris, how did you deal with this on your D250?
Thanks Carl
Dave, With 10 or 12 to 1 & wood gas, I don’t believe the heads will be an issue. I would be more concerned with valve quality, keys & retainers and valve spring tension.
Richard, I am also running a 700r4. The TV cable needs to pull at a certain ratio with the throttle, because it regulates the oil pressure. As engine horse power or load increases,the more critical the adjustment becomes. Low power vehicles have been known to get away with miss adjusted cables.
I am going to be hooked up to the WG only as I am running a 1/2 gal gas tank just for start ups.
A double linkage on a bell crank would be needed to use both throttles. Quick pin to separate.
On the D250 I had a linkage, not a cable. Since there was no good way to operate it from the woodgas throttle (I moved the carburetor too), I just left it unhooked. I could alter the shift points slightly by where I left the linkage (I set it slightly aggressive, slower to upshift). Not ideal but the truck was driveable.
Peter and Chris,
Thank you for the response. On earlier project vehicles, I have done just what Chris described.
If I only had a 1/2 gallon fuel tank, I would have been stranded several times. Peter, I recommend that you carry a few extra gallons of gasoline until you get through the 75% learning curve.
Richard,
At first I will carry a little extra gas. Gas tank capacity will be determined by the dependability of my unit.
Had to start over on the manifold ----- needed more offset. Now need to plumb in an air valve.
So far I have not found a tight enough 3.500 stainless 90* to replace the PVC. Going to try a 3 in pvc clean out next.
Lookin good Peter. Wish I could weld like that!
Thanks Don, Actually I am hoping for great improvement on the welding ------ will be getting my new glasses a week from today. Those are Helen Keller welds!!
Yahoo!! PVC conundrum solved.
Wayne, what diameter air intake to I need?
Looking good Peter!
Mine seemed to do fine at 2". I’d go with maybe a bit more, 2.5" maybe? You could go 3" if you want, but I think you’d be closing it almost all the way.
Peter, Do what I do and paint it all black. All my welds are crappy. Are you going to haul that to the salt flats to set a new record ??? I recommend small cherry chunks :o) … They deliver power and smell good to boot. I’m glad you stuck with the project. Mike
Thanks Chris, 2.500 throttle body should be readily available. Anybody have any idea what cars to check for this?
Mike, Bonneville is Wayne’s playground ------ I think I will just putter around town & maybe go for 1/4 mile drives at NED.
Yea, I will paint all my crappy welds black.
Have you been doing any DOW lately?
Howdy Peter,
Like Mike, I’m glad ya stuck around.
Looks like it could be running any day now.
Air Valve, if ya have 3" opening and ya neck it down to 2" you will find easier to mix. Like Chris said with valve mostly closed… Bigger valve may be a bit twitchy.
I can almost hear it running!
TerryL
Terry, So a 2in air valve will be barely open?